The Enslavers are among the most ancient and terrible of all warp-born horrors, predatory entities of the immaterium that hunger to invade and dominate the material universe. They are not soldiers of the Dark Gods but a distinct and primordial menace, drawn to psychic activity as sharks are drawn to blood. Where a mind burns too bright and too unguarded, an Enslaver may force a breach and haul its bloated, tentacled bulk through into reality.
Once manifest, an Enslaver seizes control of every living creature nearby, puppeting them into a shambling host of mind-thralls. These enslaved bodies exist only to protect the entity and to widen the psychic wound in reality, dragging still more Enslavers through the breach. Unchecked, a single incursion can cascade into a plague that consumes whole worlds, reducing thinking beings to hollow instruments of an alien will.
It is said that in ages past, the Enslavers rose in such numbers that they helped shatter the great empires of the ancient galaxy, and that both the Necrons and the Old Ones warred against their tide. In the 41st Millennium they remain a lurking dread, a reason the Imperium hunts and shackles its psykers so ruthlessly. For every untrained witch is a door, and behind that door the Enslavers are always waiting, patient and ravenous, for the barest crack of light.